Abstract Individuals who fall outside of the binary male/female classification of gender that matches the sex they were assigned at birth?termed transgender or simply trans?face innumerable challenges to their personal, interpersonal, and cultural identity that provoke significant health disparities. Although standards of care and other guidelines have been established for mental health services for trans individuals, these documents tend to be broad and aspirational and provide little specific information for front line providers or evidence-based practice. Furthermore, the history of stigmatization and discrimination, including in health care settings, has created many barriers to treatment seeking by trans individuals. This project seeks to reduce these health disparities and improve psychological services through two specific aims: #1 Develop culturally sensitive evidence-based principles of care for psychological services and assessment for the trans community in service impoverished areas. #2. Assess the needs and barriers for mental health services through an iterative development process in partnership with the Central Great Plains trans community that includes a deep understanding of stigma that can then inform the principles of care. Using a community-based participatory research model, the research team will partner with the Central Great Plains rural and urban trans community and local mental health providers through an iterative series of focus groups. Transcripts of the focus groups will be subjected to two analyses ? an inductive analysis based in grounded theory to identify themes and a critical, cultural, and rhetorical approach to link key topics in the transcripts to the cultural context to better understand trans stigma. The project will be guided by the already established local and national advisory boards. Deliverables include principles of care that can inform trans-affirmative adaptations of first-line psychological interventions for common disorders; a self- report instrument to inform process and outcomes for trans psychological services; and a publishable taxonomy of stigmatizing and destigmatizing discourse to provide critical information to clinicians about the way language is used to marginalize or heal trans people in the healthcare context. These deliverables and the establishment of a partnership with trans community will prepare the research team to apply the principles of care in a specific context (e.g., adapting a first-line treatment for anxiety) and, eventually, randomized controlled trials. This project will enhance public health services to a population subject to large health disparities, offering a pathway to improve best practices in mental health care for the trans population.